SP: Lesson - 3rd Declension Adjectives - Endings

3rd Declension Adjectives - Endings

3rd Declension Adjectives use 3rd declension noun endings. Specifically, they use the set of 3rd declension i-stem endings.

This is a picture of Lucius Cornelius Sulla Felix. felix is a single termination 3rd declension adjective meaning fortunate, happy, or lucky.

Think about the following questions as you learn the endings for 3rd declension adjectives.

• What features from 3rd declension i-stem nouns apply to these adjective endings?
• What is the difference between masculine and feminine 3rd declension endings?
• What is the value of knowing the three types of termination?

Third Declension Adjective Endings

	Masculine		Feminine		Neuter
Case	Singular	Plural	Singular	Plural	Singular	Plural
Nominative	er, is, x, ns, rs	es	is, x, ns, rs	es	e, x, ns, rs	ia
Genitive	is	ium	is	ium	is	ium
Dative	i	ibus	i	ibus	i	ibus
Accusative	em	es	em	es	Same As Nom	ia
Ablative	i	ibus	i	ibus	i	ibus
Vocative	Same As Nom	es	Same As Nom	es	Same As Nom	ia

Note Bene:

1. Note the following features which 3rd declension adjectives share with 3rd declension i-stem nouns:
   • Ablative singular for all genders = -i
   • Genitive plural for all genders = -ium
   • Neuter Nominative and Accusative plural ends in -ia
2. Nominative case endings are far more regular than they are for 3rd declension nouns. Instead of there being a large variety of possibilities, the nominative singular ending depends on the termination of the adjective. Therefore, there are only three possible sets of nominative endings:
   • Triple Termination has three unique nominative endings:
     • er, is, e
     • ex: acer, acris, acre
   • Double Termination has just two unique nominative endings, with masculine and feminine being the same ending:
     • is, e
     • ex: omnis, omne
   • Single Termination uses the same ending for all genders and will be one of three endings:
     • x, ns, or rs
     • ex: audax; ingens; discors
3. The masculine and feminine endings are identical in every case. The only exception is the nominative singular for triple termination adjectives (masculine = er; feminine = is).

Adjective Base for Third Declension Adjectives

Let's explore how to obtain the noun base for 3rd declension adjectives.

• For Triple and Double Termination: remove the feminine nominative ending -is:
  • acer, acris, acre
    • acris - is = acr-
  • fortis, forte
    • fortis - is = fort-
    • Remember: fortis is both the masculine AND feminine form for this double termination adjective
• For Single Termination: remove the genitive singular ending (genitive form will be provided) - remove -is:
  • audax (gen. audacis)
  • audacis - is = audac-